1. Field of the Invention
The present invention relates generally to devices for shading windows from sunlight, and more particularly, to an improved shading device which blocks direct sunlight while increasing passage of indirect light.
2. Description of the Related Art
Window blinds have long been available for reducing the harsh glare, and thermal heat, associated with the penetrating rays of the sun. For example, U.S. Pat. No. 169,502 to Widemann in the year 1875 discloses a venetian shade including a series of parallel slats for blocking direct rays of the sun. U.S. Pat. No. 2,749,581 issued to McCormick in 1956 discloses a form of vertical blinds wherein the louvers are disposed vertically.
Awning structures have also been used on the outside of buildings adjacent windows for controlling the passage of sunlight through the window. U.S. Pat. No. 2,242,697 issued to Duca in 1940 describes an awning, including a series of horizontal metal slats, that can either be lowered against the window to serve as a storm blind or raised at an angle to the window to function as a conventional awning. The awning panel includes louvers that rotate about horizontal axes for selecting how much light to admit through the window. The awning frame also pivots about a horizontal axis from just above the top of the window, and an adjustable extension rod allows a user to set the angle of the awning relative to the window. U.S. Pat. No. 2,339,878 to Reid, et al., also discloses an awning structure in which the frame can swing relative to the window, and wherein the horizontal slats can be moved between opened and closed positions. U.S. Pat. No. 6,421,966 issued to Braunstein, et al. discloses a louvered sunshade for shading window exteriors.
U.S. Pat. No. 2,301,568 to Moss discloses the use of sliding slatted shutter panels on be rolled in front of the window, or, alternatively, to the side of the window.
U.S. Pat. No. 2,654,425 to Hayner discloses a metal awning that, in one embodiment (see FIGS. 5, 6 and 10) has louvers that can be drawn to opposing sides of the awning frame or extended across the awning frame. Hayner's awning frame maintains a fixed angular relationship with the window adjacent thereto. In U.S. Pat. No. 2,791,009 to Wagner, a louver type awning is disclosed wherein the louvers themselves can be rotated about their horizontal axes, but wherein the awning frame itself is fixed relative to the window.
Some shade device developers have attempted to provide louvered shading devices which are responsive to the position and/or intensity of the sun. For example, U.S. Pat. Nos. 2,917,795 and 3,177,367, both issued to Brown, disclose light passage louvers for a window along with a control apparatus for controlling the rotation of such louvers in response to the position of the sun. U.S. Pat. No. 3,917,942 to McCay likewise discloses a sun tracking control system for regulating the position of shading vanes. Likewise, U.S. Pat. No. 4,505,255 to Baer discloses a solar actuated louver system wherein a control apparatus responsive to movement of the sun controls the rotation of parallel louvers that either block or admit direct sunlight, depending upon the season.
Awning structures that include more than one bank of louvers are also known. For example, U.S. Pat. No. 5,873,202 to Parks discloses an embodiment of an awning-type structure that includes three sets of louvers; a center louver set is fixed in position, while the surrounding outer and inner louver sets are slidably movable under manual control to vary the amount of light passed.
Solar collection systems are also known using two or more sets of louvers. In U.S. Pat. No. 4,279,240 to Artusy, a solar collector window device is disclosed for controlling passage of solar radiation and which includes a series of outer reflective planar vanes plus a series of inner insulating planar panels. The inner insulating panels are provided to prevent heat loss from inside a building when the sun is not present. The outer reflective vanes may be rotated synchronously with each other, and the inner insulating panels may be rotated synchronously with each other. A control mechanism is also disclosed for controlling the angle of inclination of the outer vanes and inner vanes. In U.S. Pat. No. 4,220,137 to Tesch, et al., a solar energy collection system is disclosed wherein two sets of louvers are mounted in a window structure. The first set of outer louvers is mounted vertically and serve to reflect radiation from the sun toward the inside of the room; these outer louver are rotated about their vertical axes to follow movements of the sun. The second set of inner louvers are mounted horizontally and reflect radiation from the sun onto a solar collector; these inner louvers may also be rotated about their horizontal axes to follow movements of the sun.
While those skilled in the art have proposed a number of different shade devices for blocking the passage of excess sunlight through a window, the majority of such prior attempts are inefficient and/or objectionable. For example, while some known shade devices may be effective in blocking the passage of sunlight through a window into the interior space of a home or commercial building, they also interfere with an occupant's view through the window. Other known shade devices may likewise be effective at blocking passage of direct rays of sunlight into a building, but also block indirect light that could be used to help illuminate the interior space, and thereby reduce amounts spent for lighting the interior space. Still other known shade devices may be effective at shading direct sunlight during certain hours of the day, or during certain seasons of the year, but lose their effectiveness during the remaining hours of the day, or during the remaining seasons of the year. Other known shade devices require extensive modification of existing windows within a building, or are otherwise complex and expensive.
Accordingly, it is an object of the present invention to provide a shade apparatus for shading a window of a building from the sun which effectively shades direct rays of the sun from passing into a window while minimizing interference of an occupant's view of the exterior through such window.
Another object of the present invention is to provide such a shade apparatus which maximizes passage of indirect ambient light through the window, to help illuminate the interior space, while simultaneously blocking out direct rays of the sun.
Still another object of the present invention is to provide such a shade apparatus capable of effectively shading direct sunlight from entering through the building window during substantially all hours of the day, and during substantially all seasons of the year, while nonetheless maximizing the passage of indirect light through such window.
Yet another object of the present invention is to provide such a shade apparatus which is relatively simple and inexpensive, and which does not require modification of windows already existing in a building.
A further object of the present invention is to provide such a shade apparatus which may be assembled in modular form to synchronously shade a significant number of windows in a relatively large commercial building.
A still further object of the present invention is to provide such a shade apparatus which may simultaneously generate clean electrical power by maintaining associated photovoltaic panels oriented directly toward the sun during substantially all daylight hours.
These and other objects of the present invention will become more apparent to those skilled in the art as the description of the present invention proceeds.